1. Technical Field
The present invention relates to a liquid ejecting apparatus that ejects liquid by applying a drive signal to an actuator and is appropriate for a liquid ejecting printing apparatus that prints predetermined text, images, or the like by ejecting, for example, a fine liquid from the nozzles of a liquid ejecting head so as to form minute particles (dots) on a printing medium.
2. Related Art
In liquid ejecting printing apparatuses, in order to eject liquid from nozzles of a liquid ejecting head, an actuator such as a piezoelectric device is disposed, and a predetermined drive signal must be applied to the actuator. Thus, in order to supply power that is necessary for driving the piezoelectric device, power amplification is performed by a power amplifier circuit. In JP-A-2007-168172, pulse modulation is performed for a drive waveform signal by a Modulator so as to acquire a modulated signal by using a digital power amplifier that has an extremely small power loss and can be miniaturized, compared to an analog power amplifier, the power of the modulated signal is amplified by using the digital power amplifier so as to acquire a amplified digital signal, and the amplified digital signal modulated signal is smoothed by using a low pass filter so as to acquire a drive signal.
As the modulated signal for the digital power amplifier, for example, a pulse-width modulated signal is used. At this time, the output voltage has a value calculated by multiplying the power source voltage of the digital power amplifier by the duty ratio of the pulse-width modulation. In other words, an arbitrary output voltage can be acquired by controlling the duty ratio of the pulse-width modulation by using the power source voltage. However, in consideration of the efficiency as a drive signal output circuit, the power source voltage supplied to the digital power amplifier is preferably low in the range in which the output voltage can be assured. In the liquid ejecting apparatus disclosed in JP-A-2007-168172, there is room for improvement of the power source voltage.